1. Field of the Invention
This invention relates to doors which can be automatically opened upon detecting a person near the door, and then closed again after the person either passes through the door or moves out of the detector range. More particularly, the present invention relates to two-panel doors, in which the opening or closing motion of the panels includes a combination of both a sliding motion and a rotational motion around a vertical axis.
2. Background Information
In areas which are accessible to public traffic, e.g. supermarkets, shopping centers and similar structures, there are frequently doors with sliding and/or pivoting panels. Such doors, after receiving a sensor signal that generally indicates the presence of a person or object near the door, execute an opening motion.
For sliding doors, this opening motion brings the panels into an open position by means of a lateral sliding motion. In such a sliding motion, the panels are retracted into recesses located laterally in relation to the open doorway and specifically provided for that purpose. Such sliding doors have the principal disadvantage that it is necessary to provide these recesses for the lateral motion of the doors. Also, such sliding doors have the disadvantage that they are operated electrically, and an event, such as a fire, which could panic the occupants of the building and put the occupants in danger, could also cause the electricity to possibly be interrupted. After such an interruption of power, it is practically impossible for the occupants of the building to open the doors, which are generally made of glass. Further, such a situation could lead to serious injuries if the glass panels were broken in order to provide access to or from the building.
To eliminate this disadvantage of sliding doors, the prior art discloses two-panel doors with devices by means of which, as the door is opening, the panels execute a combined sliding and rotational motion around a vertical axis of rotation. With such arrangements, the door panels move from a position oriented perpendicular to the door frame and across the passageway, into a position oriented parallel to the door frame and the passageway. With such doors, it is generally not necessary to provide lateral recesses to hold the door panels. However, such doors have the disadvantage of being difficult to equip with safety devices that can be used in the event of panic situations. Such safety devices are essentially necessary to make it possible to open the door panels easily even in the event of a power failure, i.e. by exerting a slight pressure on the door panels from the side of the door facing the inside of the room.
A two-panel door of this type is disclosed in German Laid Open Patent Application No. 28 05 973. On this door, the hinge joints are each located on the free end of a bracket anchored rigidly to the door panel, which bracket projects beyond a broad side of the door panel within a broad side projection. The distance from the axis of rotation of the hinge joints to the broad side of the door and to the vertical edge of the broad side projection of the door panel thereby exceeds one-sixth of the width of the door panel. As a result of this configuration and the orientation of the hinge joints, during the opening motion of each door panel, the vertically-running edge of its vertical door panel facing the opening edge in the vicinity of this opening edge swings toward one side of, namely the outside of the doorway. Simultaneously, in the central area of the door opening, the vertically-running door panel edge pivots to the other side, namely to the inner edge of the doorway. While the pivoting range toward the outside, in the vicinity of the opening edge, restricts the passageway practically not at all, the pivoting movement through the doorway directed toward the inside is significantly reduced in terms of its pivoting space. In an emergency, this door can also be pushed open manually, but because the bracket is connected to the door at a distance from the center of rotation of the door, a pressure must be applied to the door panel near the forward edge of the door panel to open the door, because that is where the force required to open the door panel is the lowest. If pressure were applied against the glass pane in the center of the door panel, a very large force would have to be applied to open the door, on account of the short lever arm. But the proper application of pressure is not apparent or easy for children or older people, and in the event of a panic situation, they might not be able to open the door and thus open the evacuation and emergency route.